Secondary battery, battery pack, electronic apparatus, electric tool, electric vehicle, and power storage system

Abstract

A secondary battery including: spirally wound electrode body in which positive electrode and negative electrode are laminated via separator and spirally wound, wherein the positive electrode includes an inner circumference side positive electrode active material layer and an outer circumference side positive electrode active material layer while including a single side active material layer formation region, the ratio A/(A+B) of an area density A (mg/cm 2 ) of the inner circumference side positive electrode active material layer and an area density B (mg/cm 2 ) of the outer circumference side positive electrode active material layer, an inner diameter C (mm) of the coil opening portion, and the ratio D/E of a thickness D (μm) of the positive electrode and a thickness E (μm) of the positive electrode collector satisfy the relationship expressed in Formula 1, and a length F (mm) of the single side active material layer formation region satisfies the relationship expressed in Formula 2.

The invention is claimed as follows: 
     
       1. A secondary battery comprising:
 an electrode body in which a positive electrode and a negative electrode are laminated via a separator and wound with a coil opening portion of the electrode body as a center, 
 wherein the positive electrode includes a first positive electrode active material layer formed on a first side of a positive electrode collector and a second positive electrode active material layer formed on a second side of the positive electrode collector, and 
 wherein a ratio A/(A+B) of an area density A (mg/cm 2 ) of the first positive electrode active material layer and an area density B (mg/cm 2 ) of the second positive electrode active material layer, an inner diameter C (mm) of the coil opening portion, and a ratio D/E of a thickness D (μm) of the positive electrode and a thickness E (μm) of the positive electrode collector satisfy a relationship expressed below:
   0.380≦ A /( A+B )≦[0.593−0.007×( D/E )]×(0.03× C+ 0.87)
 
 
 wherein C is 2.5≦C≦4 and D/E is 13.333≦D/E≦20; and 
 wherein the positive electrode includes a single side active material layer formation region in which the second positive electrode active material layer is formed on a single side of an end portion of the positive electrode collector, and 
 wherein a length F (mm) of the single side active material layer formation region satisfies a relationship expressed below:
   [0.3×( D/E ) 2 −7×( D/E )+45]≦ F≦ 50.
 
 
 
     
     
       2. The secondary battery according to  claim 1 , wherein the first positive electrode active material layer is formed on an inner circumference side of the positive electrode collector, and the second positive electrode active material layer is formed on an outer circumference side of the positive electrode collector. 
     
     
       3. The secondary battery according to  claim 1 , which further satisfies a relationship expressed below:
   0.428≦ A /( A+B )≦[0.593−0.007×( D/E )]×(0.03× C+ 0.87).
 
 
     
     
       4. The secondary battery according to  claim 1 , wherein the negative electrode includes a negative electrode active material comprising at least one of silicon and tin. 
     
     
       5. The secondary battery according to  claim 1 ,
 wherein the negative electrode includes a negative electrode active material comprising tin, cobalt, and carbon, and 
 wherein an amount of carbon in the negative electrode active material is equal to or greater than 9.9 mass % and equal to or less than 29.7 mass %, an amount of cobalt to a total amount of tin and the cobalt in the negative electrode active material is equal to or greater than 20 mass % and equal to or less than 70 mass %, and a half-value width of a diffraction peak that is obtained by X-ray diffraction of the negative electrode active material is equal to or greater than 1°, and wherein a diffraction angle 2 θis equal to or greater than 20° and equal to or less than 50°. 
 
     
     
       6. The secondary battery according to  claim 1 , which is a lithium ion secondary battery. 
     
     
       7. A battery pack comprising:
 the secondary battery according to  claim 1 ; 
 a control section that controls the secondary battery; and 
 an outer packaging that contains the secondary battery. 
 
     
     
       8. An electronic apparatus comprising the secondary battery according to  claim 1  as a power source. 
     
     
       9. An electric tool comprising the secondary battery according to  claim 1  as a power source. 
     
     
       10. An electric vehicle comprising the secondary battery according to  claim 1  as a power source. 
     
     
       11. A power storage system comprising the secondary battery according to  claim 1  as a power storage source. 
     
     
       12. A secondary battery comprising:
 an electrode body in which a positive electrode and a negative electrode are laminated via a separator and wound with a coil opening portion of the electrode body as a center, 
 wherein the positive electrode includes a first positive electrode active material layer formed on a first side of a positive electrode collector and a second positive electrode active material layer formed on a second side of the positive electrode collector, 
 wherein the positive electrode includes a single side active material layer formation region in which the second positive electrode active material layer is formed on a single side of an end portion of the positive electrode collector, and 
 wherein a ratio D/E of a thickness D (μm) of the positive electrode and a thickness E (μm) of the positive electrode collector and a length F (mm) of the single side active material layer formation region satisfy a relationship expressed below:
   [0.3×( D/E ) 2 −7×( D/E )+45]≦ F≦ 50.
 
 
 
     
     
       13. The secondary battery according to  claim 12 , wherein the first positive electrode active material layer is formed on an inner circumference side of the positive electrode collector, and the second positive electrode active material layer is formed on an outer circumference side of the positive electrode collector. 
     
     
       14. The secondary battery according to  claim 12 , wherein the negative electrode includes a negative electrode active material comprising at least one of silicon and tin. 
     
     
       15. A battery pack comprising:
 the secondary battery according to  claim 12 ; 
 a control section that controls the secondary battery; and 
 an outer packaging that contains the secondary battery. 
 
     
     
       16. An electronic apparatus comprising the secondary battery according to  claim 12  as a power source. 
     
     
       17. An electric tool comprising the secondary battery according to  claim 12  as a power source. 
     
     
       18. An electric vehicle comprising the secondary battery according to  claim 12  as a power source. 
     
     
       19. A power storage system comprising the secondary battery according to  claim 12  as a power storage source.